The Bowline

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Uses: The Bowline (ABOK # 1010, p 186) makes a reasonably secure loop in the end of a piece of rope. It has many uses, e.g., to fasten a mooring line to a ring or a post. Under load, it does not slip or bind. With no load it can be untied easily. Two bowlines can be linked together to join two ropes. Its principal shortcoming is that it cannot be tied, or untied, when there is a load on the standing end. It should therefore be avoided when, for example, a mooring line may have to be released under load.

One Handed: The bowline can be tied with one hand - useful if injured, essential if you are using the other hand to hold on to the line or the boat!

Can Untie If Not Loaded: A bowline makes a poor safety knot for a swimmer. When a bowline is unloaded, it can very readily work its way untied - I know, it has happened to me! Fortunately I only lost a scrubbing brush.

Alternative Structures: When tied as shown in the illustrations above, the bitter end lies in the middle of the loop. Passing the end the opposite way round the standing end forms a "Dutch Marine" or "Left Handed" bowline (see right). It performs satisfactorily - the Dutch Navy says better - but is much less used in other countries.

Safety: An intermittent load, e.g., on a mooring line, may cause many knots to slip or loosen. The bowline is relatively tolerant of such stresses. Nevertheless some texts quote a rule of thumb which states that the loose end should be as long as 12 times the circumference for the sake of safety. The principle is sound but, for a half inch diameter rope, this would indicate a tail more than eighteen inches long and this is rarely seen in practice.

Another recommendation is that when used for man-carrying applications a figure of eight knot should be tied in the loose (bitter) end, or, perhaps most secure of all, the free end should be fastened to the adjoining loop with a double overhand knot (picture on left) - see Climbing Section